As is well known to those skilled in the art, coking or fluid catalytic cracking (FCC) produce a cracked naphtha. This stream is one of the blending components to the gasoline pool; and it may typically be as much as 35-40% of the total gasoline pool. Cracked naphtha typically contains sulfur in amount of as much as 1000-4000 wppm; and this stream is typically a major contributor of sulfur to the gasoline pool--the other 60-65% of the pool typically contains much lower quantities of sulfur.
Cracked naphtha (including coker naphtha) typically also contains a significant concentration of olefins which desirably contribute to the octane number of the gasoline pool.
Conventional processes which attempt to hydrodesulfurize cracked naphtha charge are found typically to undesirably effect hydrogenation of the olefin components of the charge.
Typical prior art processes for hydrodesulfurizing charge cracked naphtha include those disclosed in U.S. Pat. No. 4,132,632 to Yu et al and U.S. Pat. No. 4,140,626 to Bertolacini et al--both assigned to Standard Oil Company (Ind.).
These patents disclose a hydrodesulfurization process wherein the catalyst contains VI-B and VIII metals on a support which is at least 70 w % magnesium oxide and which may also contain other refractory inorganic oxides such as alumina, silica, or silica/alumina.
It is an object of this invention to provide a novel catalyst and process for hydrotreating a charge cracked naphtha. Other objects will be apparent to those skilled in the art.